This book will be mainly focussed on the properties and uses of dendrimers and dendrons. The aim of this book is to be the reference book about dendrimers applications. It will not describe all details, but it will give the reader a unique overview of what has currently been done with dendrimers, with numerous references and illustrations. It will be divided in four main parts: Part 1) Generalities, syntheses, characterizations and properties; Part 2) Applications in catalysis; Part 3) Applications for the elaboration or modification of materials; and Part 4) Applications in biology/medicine. The role of the nanometric size and the multiple functions of dendrimers on the properties will be emphasized.